In recent years, solid-state image sensors of CMOS type in which MOS transistors are utilized in pixel amplifier sections have come to be widely used in digital still cameras and video cameras. Signal transfer methods in CMOS-type solid-state image sensors include two known methods, as follows. The first method is a so-called rolling shutter scheme that involves transferring voltage signals of pixels to a vertical signal line, sequentially for each row. In such a rolling shutter scheme, the timings of signal transfer are offset for each row, and hence the exposure timings are likewise offset for each row. The second method is a so-called global shutter scheme that involves holding charge temporarily in in-pixel memories, to render simultaneous thereby the exposure timings of all pixels. Distortion-free images can be acquired, also of a subject that is moving at high speed, by utilizing a global shutter scheme.
Patent literature 1 discloses a technique for acquiring subject motion information by using a solid-state image sensor that performs signal transfer according to a rolling shutter scheme. The solid-state image sensor described in Patent literature 1 acquires subject motion information by comparing a standard image, with skipping in the row direction, and a comparative image in which signals of all rows are acquired, without skipping. Specifically, subject motion information is acquired, by comparing a standard image and a comparative image, exploiting the feature whereby comparative images exhibit a greater distortion amount in images generated with rolling shutter than is the case in standard images.